The program seeks to elucidate the pathogenesis of Reye's Syndrome in children by investigating: 1. Cerebral circulation, metabolism and electrophysiology, 2. Cerebral ammonia metabolism, 3. Lipid metabolism and hepatic energy states, 4. Virologic and immunologic problems involved, and 5. Developing an animal model of the disease in the mouse. Interrelated clinical and laboratory investigations are proposed to achieve the objectives using biological, biochemical and ultrastructural methods.